When Jewel brings the car home to show Randy, it is all covered in dirt and soot. Then as Detective Dehling pulls up in his car, you see the back of Jewel's car is shiny and clean. This is before the infamous "wash" scene, which happens as Detective Dehling is leaving.
When Detective Dehling is riding the police motorcycle to Randy's house, the extra lights besides the bike's headlight are clear like a civilian motorcycle; when he arrives at the house, the lights are back to being a police bike's red and blue.
When Randy discovers the DVD player in Greg's bedroom he opens the tray and we get a close up of a white, blank DVD, but a red, titled DVD (see Trivia) is in the tray that is shown opening and closing repeatedly after the accident.